<!-- 
    liaotuo 
    2016.09.11 
    自动调整缩放等级 实例
-->
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<style type="text/css">
body, html,#allmap {width: 100%;height: 100%;overflow: hidden;margin:0;font-family:"微软雅黑";}
</style>
<script type="text/javascript" src="http://api.map.baidu.com/api?v=2.0& ak=你自己申请的ak">
</script>
<title>地图根据标注点自适应大小</title>
</head>
<body>
<div id="allmap"></div>
</body>
</html>
<script type="text/javascript">
// 原始gps坐标
var points = [  
{"lng":112.58,"lat":26.89,"url":"http://www.baidu.com","id":1,"name":"p1"},  
{"lng":112.59,"lat":26.90,"url":"http://www.taobao.com","id":2,"name":"p2"},  
{"lng":112.57,"lat":26.88,"url":"http://www.google.com","id":3,"name":"p3"}  
]; 
// 百度坐标系坐标(地图中需要使用这个)
var bPoints = new Array();
//创建标注点并添加到地图中
function addMarker(points) {
	//循环建立标注点
	for(var i=0, pointsLen = points.length; i<pointsLen; i++) {
		var point = new BMap.Point(points[i].lng, points[i].lat); //将标注点转化成地图上的点
        bPoints.push(point); // 添加到百度坐标数组 用于自动调整缩放级别
		var marker = new BMap.Marker(point); //将点转化成标注点
		map.addOverlay(marker);  //将标注点添加到地图上
	}
}

// 根据点的数组自动调整缩放级别
function setZoom (bPoints) {
	 var view = map.getViewport(eval(bPoints));  
        var mapZoom = view.zoom;   
        var centerPoint = view.center;   
        map.centerAndZoom(centerPoint,mapZoom);  
}

//创建地图
var map = new BMap.Map("allmap");    
map.centerAndZoom(new BMap.Point(112.591886,26.905407), 14); // 设置中心点
addMarker(points);
map.addControl(new BMap.MapTypeControl());   
map.enableScrollWheelZoom(true);     

setTimeout(function(){
    setZoom(bPoints);
}, 3000)

</script>